THUMB DRIVE VS COMPACT DISC

[jaybo666]

I AM THINKING ABOUT REPLACING MY ECLIPSE 55040 WITH AN ALPINE CDE123 HEAD UNIT. THE ALPINE HAS A USB ON THE FRONT, WHAT I'M WONDERING IS HOW DOES USB SOUND COMPARED TO A CD? ALSO, HOW MUCH OF A DIFFERENCE WILL I HEAR BY GOING FROM A 8 VOLT UNIT TO A 4 VOLT UNIT? ANY FEEDBACK FOR ME?? THANKS. BY THE WAY, THE ECLIPSE IS IN AWESOME SHAPE AND IS FOR SALE ON THIS SITE

[stipud]

USB doesn't impart any sound quality itself, the question is how good is the source material. MP3s are certainly a lot worse than CDs, but FLAC or other lossless encodings are just as good.

[00goobs]

I have one of those Alpine 9887s and was wondering if the 24bit (I think it is 24bit) DAC also converts the material of an mp3 or loss less digital media, IPOD or CD changer on the Ai Net too. I am sure it is for the CDs only, but was wondering that as well since the other sources are digital.

[stipud]

It's possible, but that would mean the USB data would have to be converted into bytes that the DAC can understand (i.e. a CD). It's likely that the USB source has a separate DAC.

[Francious70]

It's likely that the USB source has a separate DAC.

Why would it? Both sources are digital and need to be converted into and analog sound wave. I would figure that one DAC would do the trick for all sources.

AS for you other question about going from 8 volt to 4 volt, you will need to reset your gains. And by having a lower output voltage the noise floor will be higher, but it's should be inaudible when the car is moving.

[stipud]

Why would it? Both sources are digital and need to be converted into and analog sound wave. I would figure that one DAC would do the trick for all sources.

AS for you other question about going from 8 volt to 4 volt, you will need to reset your gains. And by having a lower output voltage the noise floor will be higher, but it's should be inaudible when the car is moving.

The USB digital source could be formatted in MP3, etc. As such it needs to be decoded into a standard unencoded digital signal, which could very well be passed through the same DAC. Really depends on how it was built and what components it used. I'd say most likely that yes, the same DAC is used.

[ttocs]

I would guess that the sq would be just as dependant on the software that converted it as much as the hardware that did it, probably more so then the dac that is used to convert it back so you can hear it.